The inventive concept relates to a read only memory (ROM) of a semiconductor memory, and more particularly, to verification of a layout of a mask ROM.
ROM is a memory that stores data in a non-volatile manner. The ROM is capable of retaining its stored contents even in the absence of supplied power. Data stored in a mask ROM may be programmed by a semiconductor manufacturer. For example, the mask ROM may store data by forming a previously determined circuit pattern on a semiconductor. The previously determined circuit pattern may be formed by using a photo mask manufactured corresponding to data that is to be stored in the mask ROM.
The mask ROM is included in various semiconductor devices. For example, a micro-processor may include the mask ROM to store a micro-code, and a micro-controller may include the mask ROM to store a boot loader or firmware, etc. However, due to the cost incurred to manufacture the photo mask for forming the circuit pattern, the mask ROM may entail enormous cost at an initial production stage and need a long turnaround time (TAT) from designing to production. When an error occurs in the mask ROM or data (i.e., in the ROM code) stored in the mask ROM, it may be expensive to correct the error.